1. Technical Field
This disclosure relates generally to magnetic devices that utilize thin film magnetic layers with out-of-plane magnetic anisotropy, and more specifically, to methods for reducing the resistance-area product of individual layers without reducing the overall magnetoresistance of the device.
2. Description of the Related Art
Many present day magnetic devices utilize thin films with an “out-of-plane” (i.e., perpendicular to the film plane) magnetization direction, which is often referred to as perpendicular magnetic anisotropy (PMA). Such devices include, but are not limited to,
(1) various designs of magnetic random access memory (MRAM), e.g., PMA (or Partial-PMA) Spin-Torque MRAM in which such films can serve as pinned layers, reference layers, free layers, or dipole (offset-compensation) layers;
(2) various designs of PMA spin valves, tunnel valves (magnetic tunnel junctions—MTJs) and PMA media used in magnetic sensors and magnetic data storage, and;
(3) other Spintronic devices.
For these applications it is often important to employ PMA films with a large coercivity field, Hc, and anisotropy field, Hk. It is also important to reduce, as much as possible, the resistance-area product (RA) of the individual layers, high values of which reduce the overall magnetoresistance (MR) of the structure. A variety of methods have been employed to achieve this result, with various degrees of success. Examples can be found in:    U.S. Patent Application 2011/0086439 (Choi).    U.S. Pat. No. 7,750,421 (Horng et al.).    U.S. Pat. No. 7,602,033 (Zhao et al.).    U.S. Patent Application 2009/0162698 (Fukuzawa et al).